1. Technical Field
The field of art to which this invention pertains may be generally located in the class of devices relating to tools for installing rods, studs, and the like. Class 81, entitled Tools, United States Patent Office Classification, and in particular Subclass 53.2, appears to be the applicable general area of art to which the subject matter similar to this invention has been classified in the past.
2. Background Information
It is known in the construction art to employ reinforcement steel bars or anchors in holes formed in concrete, masonry, rock or the like, and to secure the reinforcement steel bars or anchors in place by a chemical adhesive material. Heretofore, one method employed for inserting a steel reinforcement bar or anchor into a hole in concrete was to place a breakable capsule filled with a chemical adhesive into the hole and then pound the reinforcement bar or anchor into the hole. A disadvantage of the method of pounding a reinforcement bar or anchor into a hole is that the capsule material is merely compacted into the hole and the chemical adhesive stays mostly in the bottom of the hole in the concrete or the like. Another method of installing a reinforcement bar in a hole in concrete and the like is to install a wrench over the free end of the bar and use a plurality of set screws to hold the wrench on the bar, and then rotate the wrench to turn the bar into the hole. A disadvantage of the last described bar installation method is that it is time consuming and costly, laborwise. A method of installing a threaded stud or anchor in a hole in concrete or the like, is shown in U.S. Pat. No. 4,404,875. A disadvantage of the drive unit of U.S. Pat. No. 4,404,875 is the fact that much time is lost on the job in having to manually release the drive unit with a pair of wrenches. The wrenches also comprise extra tools which must be employed in the use of the last mentioned drive unit.
U.S. Pat. Nos. 2,336,157, 2,933,960, 3,280,666, and 4,513,643 illustrate further examples of prior art tools for installing threaded studs and similar elements.